According to the particle model, the atoms in a solid crystal can be modeled as tightly packed spheres, where each atom effectively occupies a cubic volume of side length ddd. Here, d d\,d represents the average separation between the centers of neighboring atoms.
A crystalline silicon (Si\text{Si}Si) wafer has a density of 2330 kg m-3 and a molar mass of 28.1 g mol-1. Using the Avogadro constant NA=6.02×1023 mol−1N_A = 6.02 \times 10^{23} \text{ mol}^{-1}NA=6.02×1023 mol−1, estimate the average separation d d\,d between neighboring silicon atoms.
2.7×10−10 m2.7 \times 10^{-10} \text{ m}2.7×10−10 m
2.7×10−9 m2.7 \times 10^{-9} \text{ m}2.7×10−9 m
2.0×10−29 m2.0 \times 10^{-29} \text{ m}2.0×10−29 m
1.4×10−10 m1.4 \times 10^{-10} \text{ m}1.4×10−10 m
27 exam-style questions on OCR GCSE Chemistry The particle model. Each one has a worked solution and a mark scheme showing where the marks go.